Accession Number : ADA331619

Title :   Novel Semiconductors

Descriptive Note : Final rept. 15 Mar 94-14 Mar 97

Corporate Author : ARIZONA STATE UNIV TEMPE

Personal Author(s) : Dow, John D.

PDF Url : ADA331619

Report Date : OCT 1997

Pagination or Media Count : 6

Abstract : This report summarizes work performed on novel semiconductor materials. A new sp3d5 empirical tight-binding model of the electronic structure of silicon was developed. Models showed that the Er(+3) crystal-field splitting in Si has a different electronic structure than previously assumed in the literature. Surface reconstructions of Si have been worked out for 5-by-1 and 16-by-2, the latter of which is the largest ever described. A theory describing the role of interfacial charges in determining lattice-matching conditions at substrate surfaces was developed. The defect structure of the first successful STM image of the GaN(0001) surface on a mismatched substrate was modeled. Electronic structure calculations showed that quantum dots, which can result from controlled lattice-mismatched growth, have indirect bandstructure under certain conditions. Finally, the conventional theory of superconductivity is called into question with the determination that the primary superconducting condensate resides in the charge 'reservoir layers, as opposed to occupying the cuprate planes.

Descriptors :   *SEMICONDUCTORS, ELECTRONICS, CRYSTAL STRUCTURE, INTERFACES, MATERIALS, COMPOSITE MATERIALS, CRYSTAL LATTICES, SUBSTRATES, SURFACES, COPPER, SILICON, MOLECULAR STRUCTURE, ERBIUM, SUPERCONDUCTIVITY, CONDENSATION.

Subject Categories : Electrical and Electronic Equipment
      Crystallography
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE